Production of Ammonia 2

The industrial production of ammonia from nitrogen and hydrogen requires high temperatures, high pressures, an iron catalyst and is a reversible reaction. The nitrogen comes from the air whilst the hydrogen is usually obtained by reacting steam with natural gas. The two gases are continuously cycled and recycled through the reaction vessel. During the recycling, they are cooled to remove the ammonia and fresh nitrogen and hydrogen are added. The process is therefore continuous and you are expected to know the factors that affect the manufacturing costs. Since the equipment runs all day and every day, automating the process is a good way for manufacturers to save money. The recycling of the gases is also a simple way of keeping costs down.

The pressures and temperatures used are always a compromise in order to make the process economically worthwhile and are the key factors that increase the costs. Using higher pressures would increase the amount of ammonia produced, however, the extra cost of building the equipment that could generate and withstand such pressures would not be balanced by the sale of the extra ammonia. Energy costs could be reduced by lowering the temperature but the reaction would slow dow too much and it would not be possible to satisfy the demands of customers. The iron catalyst is useful here as it speeds up the reaction, meaning that temperatures can be kept relatively low.